Abstract: Based on studying interdependence of spray characteristics and evaporation history of fuel sprays and on measuring the spray characteristics by light scattering in heated air stream,authors conducted an experimental and analytical research on variation of spray characteristics of vaporizing kerozine sprays in a straight cylindrical vaporizer with heated air stream. The fuel was injected co-axially from a plane orifice air blast atomizer upstream of the vaporizer. Both the experimental and analytical results show that within the present parameter range, the spray Sauter Mean Diameter and drop size distribution parameter increase with downstream vaporization distance.